Process of removing finish coating



March l0. 1925.

D. P. CLEVELAND PROCESS 0F REIOVING FINISH COATING 2 Sheets-Sheet 1 Filed Sept.` 13, 1920 March l0. 1925.

D. P. CLEVELAND Pnocnss oF nsuovms FINISH comme Filed Sept. 13, 1920 2 Sheets-Sheet 2 STE/7)! DOME @ig Z Mmm/i )WA "as 'Arron rs WITNESSES Patented Mar. l0, 1925.

PATENTvv oFFlcE.

DAVID P. 'cLEvELAnn or DALLAS, TEXAS.

PMCESS O'F REMOVING FINISH GOATING.

Application led September 13, 1920. Serial No. 409,915.

To all whom z't may concern:

Be. it known that I, DAVID P. CLEVELAND, a citizen of the United States, residing at Dallas, in the county of Dallas and. State of Texas, have invented certain new and usei'ul Improvements in Processes of Removing Finish Coating', of which the following is a specification.

This invention relates to the removal of paint, varnish, lacquer and the like 'from surfaces of coated articles, and has special reference to the removal of such coatings after they have dried, and if desired after many successive repaintings, for preparing the article for repainting or refinishing. The coated articles under treatment may be carriages, automobiles, furniture, Walls, fioors or other coated objects which it is desired to repaint or refinish. The process is especially useful and effective in connection with the removal of paint and vvarnish from automobiles.

Various methods have been used, prior to the present invention, for removing finish coatings bythe use of heat and an alkali solution, but the process of the presentinvention has been found to be superior in performance and superior in results as well as much quicker in action. The invention comprises the steps of spraying a hot fixed caustic alkali upon the painted surface. under conditions to disintegrate the finish coating, and removing the reaction products and excess of caustic solution. Paints and varnislies. when the same have dried on the surfaces ot painted articles, consist largely of oxidized and' dried oils, resins, gums` etc., together with insoluble pigments and the like. The action of the hot caustic alkali on such a product is to saponjfy the organicmaterial. This is, when saponified, in solution in the water contained in the paint remover liquid, and the further amounts of water produced by condensation of steam, tend to quite thoroughly wash off the soapy solution and loosened pigment, together with whatever dirt., dust. etc.. may also be present.

The first step of my Vpresent process can readily be accomplished by introducing steam, which is preferably dryl7 in accord'- anee with the common usage of this term) into a receptacle containing an aqueous solution in which is included a fixed caustic alkali. This causes the solution to be heated somewhat and also to bev displaced from' the receptacle under steam pressure. The steamheated chemical solution is conveyed to a pipe through which live steam is passing, whereby the steam and alkali solution are mixed, 4.and converted into a diffused coarse spray (as distinguished from atomization). After the steam-heated chemical solution is mixed with the steam, the mixture is con veyed by an ordinary hose and allowed to escape from the end of the hose on to the surface being treated, no nozzle (i. e., atomizer or the like) is used and the discharge from the hose is neither atomized nor in the form of a jet of particles as small as those produced by atomization.'

It has been found that by this method the alkali becomes thoroughly mixed with the steam and thoroughly heated, and it attacks] the painted surface over a larger area and with more rapid results.

In order to carry out the process, some apparatus is necessary.

In the accompanying drawings, two forms of apparatus, for carrying out the process of my invention are shown, by way of example, of the large number of possible forms which mightbe used.

In said drawings, Fig. 1 shows a vertical elevation of' a suitable apparatus, which I consider as the preferred construction, and

Fig 2 shows a similar View of another and somewhat less desirable form of apparatus.

In Fi 1, the numeral 10 designates a suitable boiler having a steam pipe 11 leading from its upper portion. The steaml pipe enters the lower ortion of a steam drum 12. The object of this arrangement is to get socalled dry steam from the drum 12. A four-way coupling 13 is connected with the top of the drum. A steam supply pipe 11 leads from the top of the coupling to another four-Way coupling 14. A branch steam lpipe 15 leads from one side of the coupling 13, and a second steam pipe 16 leads from` the other sideA of this coupling.

y The'pipe 15 enters the top of the chemical tank 17, having a filling cap 18. A eut-oil' valve 19 is -included in the pipe 15, for ex! ample just above the tank 17. A discharge pipe 20 having a valve or cock 21, leads from the bottom of the tank 17, and is connected with the four-way connection 14a, just below a cut-off valve '147, in pipe 14.

The pipe 16 enters the top of a tank 22,

24 is included in the pipe 15, for example, i

'rj-ust above the tank 22. A discharge pipe25 leads from the bottom of the tank 22, and includes a cut-off valve 26, which may -be located adjacent said tank. This pipe is connected with the four-'Way connection 14a.

A second cut-oli valve 27 may be included in the pipe 20, adjacent to connection 14a,

admitted to the upper and a second cut-oli' valve 28may he included in the pipe 25, adjacent the connection 14,

It will be seen that when it is desired to remove the finish coating of an article, the valves 24 and 28 are closed, so that the steam cannot enter the tank 22, and therefore the contents of tank 22 cannot pass 4to the connection v14, at the. end of pipe 141 The valvev14 ,in the pipe 14, is opened,

` whereby steam Will pass from the drum and mix with the heated solution in the connection 14". An ordinary hose 29, which may' bea one-inch rubber hose, is attached to thev end of the. 4ipe 30, leiding from connectionj14, an said hose receives the steam and chemical solution in a state of admixture. An ordinary garden hose 'is very suitable for this purpose, and it is not necessary, and r apparently it is not desirable, to

employ 'any obstructions in said hose. No nozzle on the end ofthe hose is needed.

The spray is discharged from the end of' @the hosef and directed-*again st' the surface being treated. The steam will heat the 'surface and the hot solution will attack the v finish, whereby thelatter is disintegrated.

. After the finish has been substantially lall removed from the'surface, the valves 19, 21 and 27 are#closed, and the valves '24 and `26 opened. The ,valve28 is opened a regulated amount. This cuts off the supply of steamAv` tothe chemical tank 17, and the discharge from saidtank to th'epipe 14, and admits steam to'the tank 22'-, whereby'the solution in the same is heated and discharged through the pipe-25 into the connect-ion 14";

This 1s lthe washing solution (e. -g)., a solu-V tion of `ordinary washing powder and b going over the surface all traces of the free caustic alkali of the paint remover used in the first operation are quickly washed off and the surface cleaned. After this operation the surface is hwashed eliwith a stream lof ordinary water (cold or'hot). When thesurface has thoroughly dried it is ready -forrepainting. l

' The alkali solution used in the tank 17 can be varied considerably, and a con- The steam thus a mitted to Ithe .tankv venient and eiicient solution for removing paint from automobiles, the original painted surface .being metal, is made by adding ten pounds of caustic soda to every twenty-live gallons'of water. In some instances it is advisable to also add about one .and onequarter' pounds of lime, but this depends upon'the grade of the caustic soda used,

' and acts t precipitate any carbonate originally present in the caustic soda, also a small amount of dissolved lime seems to be helpful. Caustic potash could also be used as a substitute for'all or part of the caustic soda. TheI mixture is preferably made up. stirred well and settled, aftery which it may be drawn nii from any sediment or precipitate, into tank 17. The foregoing described solution. is merely one'ofthe eiicient and suitablemixtures which have been found to give .good results .in the process and the in'- vention is not limited thereto; any solution of fixed caustic alkali offsuitable degree of concentration can be employed.

The washing solution is preferably made of about one-half pound of ordinary-commercial washing powder, (e. g., mixtures ot powdered-soap, borax, soda ash. etc.. which may be bought -at almost any grocery store) totwenty-five. gallons of water. Any washing powder which would tend to wash off the slight ,(nantity of fixed caustic alkali remaining flrom the first operation, can be used, and the invention is not to be limited to any particular kind.

' .Tests of this process and apparatus show that it is possible tol remove .the aint from the body of a Ford automobi e in' nine minutes, land to remove the paint from the body, running gear4 andthe wheels, only about 'twenty-five minutesl is required. In Vv.larger cars, such as an ordinary live-paslen los l s'enger touring car, about eleven minutes is required to remove the paint entirely from the body, and abouteight Aminutes from the wheels. This does not include the running gears. .Qn' articularly lwell finished cars the work wil require a longer time; however, the inish' has been vremoved from the back panel of the. bodyof a seven-passenger touring car-in from two to three minutes.

Fig. 2 shows another form of'apparatus which' may be employed. This apparatus is substantially simpler than that shown in Fig. 1 (the preferred apparatus), but' for some purposes it works very well. 'Ihisapparatus will now'be described in connection with the operation of the simplified process.`

. 31 isa steam boiler of any ordinary construction, having an oE-take pipe 32, leading to a dry steam box or separator 33, from which steam under pressure passes b .pipe 34 valve 34 being open) into a tan r 35, containing the alkaline' paint-remover Y liquid, (which may be the same as that above described). The liquidis forced through pipe 36, containing a valve 37, into the T- union 38. lSteam (preferably dry) also passes from the dome of the boiler .through4 union or 'IT-connection 38, so that steam carrying a spray of the hot aint-remover liquid passes through the nipp c 41 and rubber hose 42, to the outlet 43 thereof.l If desired, a suitable handle .as shown at 44, may be placed: upon the hose for-convenience in handling and operating 'the same. This handle can be omitted ifv desired.

By means of this device the spra of paintremover liquid and steam is app ied -to the surface of the article from which the paint is to be removed,l which surface is kept hot Work 1s then ready for repa1nt1ng,reenamel by they excess of steam and the paint is thereby rapidly disintegrated and removed from the surface. p y

The workman holds' the handle 14 in his hand and moves the same horizontally back and forth, across the upper part of the Surface of a given area. This operation is continued, graduall working downwardly over the surface un er treatment, until a considerable amount of surface has been cleaned. This operation is continued on each portion of surface, until the paint and varnish are thoroughly removed.

During this treatment (as during the first step of themore desirable process above described, the alkali solution in contact with the Work'being treated, is maintained sublike (made of leather, artificial leather, cloth,

plush and similar materials), it is sometimes advisable to first clean ofi' a stri say a'few inches Wide, from the portions o the ainted surface adjacentto such trimmings, y any ordinary paint-removing methods.

W'hen the paint and l.varnish have been loosened and substantially all removed from the surface, or from some part thereof (say, thev back of an automobile) itJ is advisable but not necessary, to shut off the iow o paint-remover liquid to the hose, and to then go over the entire surface (which may have cooled more or less in the meantime) with a steam jet, to wash off 'adhering particles of pigment, Hakes' of loosened paint, and parfter thoroughly drying the surface, the

ing or other like operations.

' It has been found that surface from which the paint has been removed with this process will more readily take a new coating of paint.

The process of' my present application is an improvement on the process of my prior applications Serial No. 300,583, filed May 29, 1919, and 348,472, filed December 30, 1919)(now Patent No. 1,355,074, October 5, 1920 What I claim is:

A process of removing finish coating from an article, which comprises the ste of simultaneously applyin steam and a nish remover containing a di ute solution of a fixed caustic alkali to the surface of said article,

-the amount of steam being sufficient to maintain the caustic solution on the surface in substantially a boiling condition until the finish is disintegrated, then washing ofl' the surface by applying thereto steam simultaneousl commercial washing wder has ma be advisable in some cases.

with a solution comprising water been dissolved, and then Washing off the 96 surface with clear water.

In testimon whereof I aiiix my signature.

AVID P. CLEVELAND. 

